A conventionally known example of a projection type display which projects images displayed on an image display element such as liquid crystal on a screen or the like is the so-called two-light source projection display using two light sources, which is disclosed in for example Japanese Patent Laid-open No. 2001-21996. As shown in FIG. 3 of Japanese Patent Laid-open No. 2001-21996, two light-source units are arranged in opposition to each other and a plurality of, e.g., three, reflective surface elements are arranged between the two light-source units in such a manner that light emitted from the light-source units is reflected by the reflective surfaces and is incident on a plane of incidence of a first lens array plate.
The light beams incident on the first lens array plate form secondary light-source images on corresponding lenses of the second lens array plate, as shown in FIGS. 6 and 7 of Japanese Patent Laid-open No. 2001-21996. The light beam condensed on each lens is then incident on a polarization transforming element (prism array plate) and is separated to p-polarization light and s-polarization light by its polarization separating surface. At the polarization separating surface, the beam of p-polarization light travels straight ahead, while the beam of s-polarization light is reflected. By a reflective surface which follows the beam of s-polarization light is bent its optical path into the same direction as the direction of p-polarized light and is transformed into p-polarization light by a half-wave plate. Then a beam with the direction of polarization regulated to p-polarization is emitted from the polarization transforming element and is directed to a liquid crystal panel.